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1
Sinkjær, Thomas, Nikolai Gantchev, and Lars Arendt-Nielsen. "Mechanical properties of human ankle extensors after muscle potentiation." Electroencephalography and Clinical Neurophysiology/Evoked Potentials Section 85, no. 6 (1992): 412–18. http://dx.doi.org/10.1016/0168-5597(92)90055-g.
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Martelli, Taborri, Del Prete, Palermo, and Rossi. "Quantifying Age-Related Differences of Ankle Mechanical Properties Using a Robotic Device." Robotics 8, no. 4 (2019): 96. http://dx.doi.org/10.3390/robotics8040096.
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A deep analysis of ankle mechanical properties is a fundamental step in the design of an exoskeleton, especially if it is to be suitable for both adults and children. This study aims at assessing age-related differences of ankle properties using pediAnklebot. To achieve this aim, we enrolled 16 young adults and 10 children in an experimental protocol that consisted of the evaluation of ankle mechanical impedance and kinematic performance. Ankle impedance was measured by imposing stochastic torque perturbations in dorsi-plantarflexion and inversion-eversion directions. Kinematic performance was assessed by asking participants to perform a goaldirected task. Magnitude and anisotropy of impedance were computed using a multipleinput multiple-output system. Kinematic performance was quantified by computing indices of accuracy, smoothness, and timing. Adults showed greater magnitude of ankle impedance in both directions and for all frequencies, while the anisotropy was higher in children. By analyzing kinematics, children performed movements with lower accuracy and higher smoothness, while no differences were found for the duration of the movement. In addition, adults showed a greater ability to stop the movement when hitting the target. These findings can be useful to a proper development of robotic devices, as well as for implementation of specific training programs.
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Becerra, J. G. Flores, N. López Perrusquia, M. A. Doñu Ruiz, A. López Perrusquia, and J. V. Cortes Suarez. "Study of Microstructure and Mechanical Properties of an Ankle Prosthesis Removing." MRS Proceedings 1766 (2015): 19–25. http://dx.doi.org/10.1557/opl.2015.408.
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ABSTRACTThis work studies the change microstructural and mechanical properties of an ankle prosthetic material 316LVM stainless steel, retired from a 36 year old patient. The medical grade 316LVM stainless steel was characterized by scanning electron microscopy (SEM), optical microscopy (OM), X-ray diffraction (XRD), hardness Rockwell C (HRC) and nanoindentation tests. The results showed that the ankle prosthesis has different microstructural change along the implant and presence of corrosion pits with inclusions, the mechanical properties like modulus elasticity and hardness decrease.
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Sheehan, Conor, and Elaine Figgins. "A comparison of mechanical properties between different percentage layups of a single-style carbon fibre ankle foot orthosis." Prosthetics and Orthotics International 41, no. 4 (2016): 364–72. http://dx.doi.org/10.1177/0309364616652015.
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Background:Currently, a range of ‘off-the-shelf’ ankle foot orthoses are used in clinical practice, of various functions and designs. Their use relates to immediate control over mild conditions.Objectives:To investigate the properties of carbon fibre ankle foot orthoses at different percentage layups and provide a comparison of these through assessment of the (1) elastic properties, (2) deflection about the ankle (including the calculation of stiffness) and (3) failure under compressive forces (dorsiflexion).Study design:Experimental, bench test.Methods:Literature was reviewed to derive a suitable bench test for mechanical testing of ankle foot orthoses. Two universal Instron machines were used to apply the necessary forces. A pilot device was utilised to establish the range of forces appropriate to confirm the setup chosen was effective. Each test was then carried out on nine ankle foot orthoses (3 × 3 different percentage layups).Results:All nine devices had their elastic properties deduced. Stiffness exhibited greater resistance in tension, with angular deflection being greatest in the ‘Lite’ set and least in the Rigid. Failure occurred mainly due to fracture, proximally on the strut; however, this was not consistent among the devices.Conclusion:Results confirmed the properties expected of carbon fibre ankle foot orthoses were consistent. This can now be related to functionality and therefore specific device prescription options.Clinical relevanceThis article attempts to increase the understanding and develop the area of mechanically testing ankle foot orthoses. This was achieved by comparing carbon fibre at different percentage layups on an identical design and their resultant structural properties. This article outlines a clear and simple setup for obtaining repeatable results.
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Wang, Ruoli, Shiyang Yan, Marius Schlippe, et al. "Passive Mechanical Properties of Human Medial Gastrocnemius and Soleus Musculotendinous Unit." BioMed Research International 2021 (February 9, 2021): 1–12. http://dx.doi.org/10.1155/2021/8899699.
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The in vivo characterization of the passive mechanical properties of the human triceps surae musculotendinous unit is important for gaining a deeper understanding of the interactive responses of the tendon and muscle tissues to loading during passive stretching. This study sought to quantify a comprehensive set of passive muscle-tendon properties such as slack length, stiffness, and the stress-strain relationship using a combination of ultrasound imaging and a three-dimensional motion capture system in healthy adults. By measuring tendon length, the cross-section areas of the Achilles tendon subcompartments (i.e., medial gastrocnemius and soleus aspects), and the ankle torque simultaneously, the mechanical properties of each individual compartment can be specifically identified. We found that the medial gastrocnemius (GM) and soleus (SOL) aspects of the Achilles tendon have similar mechanical properties in terms of slack angle (GM: − 10.96 ° ± 3.48 ° ; SOL: − 8.50 ° ± 4.03 ° ), moment arm at 0° of ankle angle (GM: 30.35 ± 6.42 mm; SOL: 31.39 ± 6.42 mm), and stiffness (GM: 23.18 ± 13.46 Nmm-1; SOL: 31.57 ± 13.26 Nmm-1). However, maximal tendon stress in the GM was significantly less than that in SOL (GM: 2.96 ± 1.50 MPa; SOL: 4.90 ± 1.88 MPa, p = 0.024 ), largely due to the higher passive force observed in the soleus compartment (GM: 99.89 ± 39.50 N; SOL: 174.59 ± 79.54 N, p = 0.020 ). Moreover, the tendon contributed to more than half of the total muscle-tendon unit lengthening during the passive stretch. This unequal passive stress between the medial gastrocnemius and the soleus tendon might contribute to the asymmetrical loading and deformation of the Achilles tendon during motion reported in the literature. Such information is relevant to understanding the Achilles tendon function and loading profile in pathological populations in the future.
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Ielapi, Alessio, Malcolm Forward, and Matthieu De Beule. "Computational and experimental evaluation of the mechanical properties of ankle foot orthoses: A literature review." Prosthetics and Orthotics International 43, no. 3 (2019): 339–48. http://dx.doi.org/10.1177/0309364618824452.
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Background: Ankle foot orthoses are external medical devices applied around the ankle joint area to provide stability to patients with neurological, muscular, and/or anatomical disabilities, with the aim of restoring a more natural gait pattern. Study design: This is a literature review. Objectives: To provide a description of the experimental and computational methods present in the current literature for evaluating the mechanical properties of the ankle foot orthoses. Methods: Different electronic databases were used for searching English-language articles realized from 1990 onward in order to select the newest and most relevant information available. Results: A total of 46 articles were selected, which describe the different experimental and computational approaches used by research groups worldwide. Conclusion: This review provides information regarding processes adopted for the evaluation of mechanical properties of ankle foot orthoses, in order to both improve their design and gain a deeper understanding of their clinical use. The consensus drawn is that the best approach would be represented by a combination of advanced computational models and experimental techniques, capable of being used to optimally mimic real-life conditions. Clinical relevance In literature, several methods are described for the mechanical evaluation of ankle foot orthoses (AFOs); therefore, the goal of this review is to guide the reader to use the best approach in the quantification of the mechanical properties of the AFOs and to help gaining insight in the prescription process.
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Siegler, Sorin, John Block, and Carson D. Schneck. "The Mechanical Characteristics of the Collateral Ligaments of the Human Ankle Joint." Foot & Ankle 8, no. 5 (1988): 234–42. http://dx.doi.org/10.1177/107110078800800502.
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In the present study, the tensile mechanical properties of all of the collateral ligaments of the human ankle joint were determined, in vitro, from tensile tests conducted on 120 ligaments obtained from 20 fresh lower limbs. The ultimate load of the lateral collateral ligaments increased in an anteroposterior sequence, with the anterior fibulotalar ligament less than the fibulocalcaneal ligament and less than the posterior fibulotalar ligament. For the medial collateral ligaments, the increasing order of ultimate load was found to be tibiocalcaneal ligament, tibionavicular ligament, tibiospring ligament, posterior tibiotalar ligament. The posterior tibiotalar ligament and tibiospring ligament, so frequently neglected in the anatomical and orthopaedic literature, demonstrated the highest yield force and ultimate load of all of the collateral ligaments of the ankle. Additionally, the tibiospring ligament showed high yield and ultimate elongation properties probably related to its distal attachment to the spring ligament. The fibulocalcaneal ligament was found to have high linear elastic modulus suggesting some type of unique material properties or internal fiber organization. Knowledge of the mechanical characteristics of the ligaments of the ankle joint contributes to an understanding of their normal function, pathomechanics of injury, and their optimal surgical reparative procedure and reconstructive material. A knowledge of the normal mechanical properties of the ankle ligaments provides a data base to evaluate which of the multiplicity of present tendon graft materials has mechanical properties similar to those of the ligaments to be replaced. Those tendon grafts will be the most suitable for replacement of specific ligaments. Finally, data on the mechanical properties of these ligaments offer the possibility for evaluating any future biological or prosthetic grafts.
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Jeryo, Abbas H., Jumaa S. Chiad, and Wajdi S. Abbod. "Boosting Mechanical Properties of Orthoses - Foot Ankle by Adding Carbon Nanotube Particles." Materials Science Forum 1039 (July 20, 2021): 518–36. http://dx.doi.org/10.4028/www.scientific.net/msf.1039.518.
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In this process, optimum laminating properties were used in producing prosthesis and orthoses were researched and selected based on high yield, ultimate stresses, stresses of bending and fatigue properties. The process of the optimal selection is the Response Surface Methodology (RSM), which has been used to reach two parameters: reinforcement perlon fiber and percent of multi-strand carbon MWCNT nanotube combined with the matrix resin. The response surface methodology is a combination of mathematician and statistic techniques which are used for experimental model building and analysis of problems. This technique revealed 13 separate laminations samples with a percentage of separate Perlon layers No. and MWCNT Wt %. Tests were conducted for all lamination materials as defined in RSM methods and rendered by vacuum system, including fatigue tests for the ideal laminating material as opposed to laminations developed in the prior study (three Tensile test, Bending test and Fatigue tests according to the ASTM D638 and D790 respectively). Tests from the system version 10.0.2 of Design Expert found lamination (10 perlon layers and 0.75% of MWCNTs) to be the best according to overall yield, ultimate and bending loads in the 12 other laminations. Fatigue eventually revealed that constraints were applied to the stamina tension (2,66, 1,66) for optimum lamination, relative to ten perlon lamination layers and 424 lamination respectively.
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Kovaleski, John E., Robert J. Heitman, Larry R. Gurchiek, J. M. Hollis, Wei Liu, and Albert W. Pearsall IV. "Joint Stability Characteristics of the Ankle Complex After Lateral Ligamentous Injury, Part I: A Laboratory Comparison Using Arthrometric Measurement." Journal of Athletic Training 49, no. 2 (2014): 192–97. http://dx.doi.org/10.4085/1062-6050-49.2.07.
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Context: The mechanical property of stiffness may be important to investigating how lateral ankle ligament injury affects the behavior of the viscoelastic properties of the ankle complex. A better understanding of injury effects on tissue elastic characteristics in relation to joint laxity could be obtained from cadaveric study. Objective: To biomechanically determine the laxity and stiffness characteristics of the cadaver ankle complex before and after simulated injury to the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) during anterior drawer and inversion loading. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: Seven fresh-frozen cadaver ankle specimens. Intervention(s): All ankles underwent loading before and after simulated lateral ankle injury using an ankle arthrometer. Main Outcome Measure(s): The dependent variables were anterior displacement, anterior end-range stiffness, inversion rotation, and inversion end-range stiffness. Results: Isolated ATFL and combined ATFL and CFL sectioning resulted in increased anterior displacement but not end-range stiffness when compared with the intact ankle. With inversion loading, combined ATFL and CFL sectioning resulted in increased range of motion and decreased end-range stiffness when compared with the intact and ATFL-sectioned ankles. Conclusions: The absence of change in anterior end-range stiffness between the intact and ligament-deficient ankles indicated bony and other soft tissues functioned to maintain stiffness after pathologic joint displacement, whereas inversion loading of the CFL-deficient ankle after pathologic joint displacement indicated the ankle complex was less stiff when supported only by the secondary joint structures.
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Kobayashi, Toshiki, Fan Gao, Nicholas LeCursi, K. Bo Foreman, and Michael S. Orendurff. "Effect of Shoes on Stiffness and Energy Efficiency of Ankle-Foot Orthosis: Bench Testing Analysis." Journal of Applied Biomechanics 33, no. 6 (2017): 460–63. http://dx.doi.org/10.1123/jab.2016-0309.
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Understanding the mechanical properties of ankle-foot orthoses (AFOs) is important to maximize their benefit for those with movement disorders during gait. Though mechanical properties such as stiffness and/or energy efficiency of AFOs have been extensively studied, it remains unknown how and to what extent shoes influence their properties. The aim of this study was to investigate the effect of shoes on stiffness and energy efficiency of an AFO using a custom mechanical testing device. Stiffness and energy efficiency of the AFO were measured in the plantar flexion and dorsiflexion range, respectively, under AFO-alone and AFO-Shoe combination conditions. The results of this study demonstrated that the stiffness of the AFO-Shoe combination was significantly decreased compared to the AFO-alone condition, but no significant differences were found in energy efficiency. From the results, we recommend that shoes used with AFOs should be carefully selected not only based on their effect on alignment of the lower limb, but also their effects on overall mechanical properties of the AFO-Shoe combination. Further study is needed to clarify the effects of differences in shoe designs on AFO-Shoe combination mechanical properties.
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Olesen, Annesofie T., Bente R. Jensen, Toni L. Uhlendorf, Randy W. Cohen, Guus C. Baan, and Huub Maas. "Muscle-specific changes in length-force characteristics of the calf muscles in the spastic Han-Wistar rat." Journal of Applied Physiology 117, no. 9 (2014): 989–97. http://dx.doi.org/10.1152/japplphysiol.00587.2014.
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The purpose of the present study was to investigate muscle mechanical properties and mechanical interaction between muscles in the lower hindlimb of the spastic mutant rat. Length-force characteristics of gastrocnemius (GA), soleus (SO), and plantaris (PL) were assessed in anesthetized spastic and normally developed Han-Wistar rats. In addition, the extent of epimuscular myofascial force transmission between synergistic GA, SO, and PL, as well as between the calf muscles and antagonistic tibialis anterior (TA), was investigated. Active length-force curves of spastic GA and PL were narrower with a reduced maximal active force. In contrast, active length-force characteristics of spastic SO were similar to those of controls. In reference position (90° ankle and knee angle), higher resistance to ankle dorsiflexion and increased passive stiffness was found for the spastic calf muscle group. At optimum length, passive stiffness and passive force of spastic GA were decreased, whereas those of spastic SO were increased. No mechanical interaction between the calf muscles and TA was found. As GA was lengthened, force from SO and PL declined despite a constant muscle-tendon unit length of SO and PL. However, the extent of this interaction was not different in spastic rats. In conclusion, the effects of spasticity on length-force characteristics were muscle specific. The changes observed for GA and PL muscles are consistent with the changes in limb mechanics reported for human patients. Our results indicate that altered mechanics in spastic rats cannot be attributed to differences in mechanical interaction, but originate from individual muscular structures.
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Hoang, Phu D., Michael Psarakis, Li Khim Kwah, Jillian L. Clarke, Simon C. Gandevia, and Joanna Diong. "Brief report: Passive mechanical properties of gastrocnemius in multiple sclerosis and ankle contracture." Clinical Biomechanics 84 (April 2021): 105338. http://dx.doi.org/10.1016/j.clinbiomech.2021.105338.
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Kwah, Li Khim, Robert D. Herbert, Lisa A. Harvey, et al. "Passive Mechanical Properties of Gastrocnemius Muscles of People With Ankle Contracture After Stroke." Archives of Physical Medicine and Rehabilitation 93, no. 7 (2012): 1185–90. http://dx.doi.org/10.1016/j.apmr.2012.02.009.
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M. Takhakh, Ayad, and Saif M. Abbas. "Manufacturing and analysis of carbon fiber knee ankle foot orthosis." International Journal of Engineering & Technology 7, no. 4 (2018): 2236. http://dx.doi.org/10.14419/ijet.v7i4.17315.
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Knee ankle foot orthoses (KAFOs) are used by paraplegia patients with low level spinal cord injury and having well control of the stem muscles. Four layers of carbon fiber with C- orthocryl lamination resin are used for manufacturing the knee ankle foot orthoses in this work. The mechanical properties of most of the components materials were estimated with the aid of fatigue and tensile test machines. Results of the tensile tests showed that the mechanical properties: yield stress, ultimate strength and modulus of elasticity were 92MPa, 105.7MPa and 2GPa respectively. The value of amidst pressure between the patient limb and the manufactured KAFO was measured using (F-socket) Mat scan sensor and these values of pressure were (663kPa) and (316kPa) for the thigh and calf regions respectively.
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Gao, Fan, William Carlton, and Susan Kapp. "Effects of joint alignment and type on mechanical properties of thermoplastic articulated ankle-foot orthosis." Prosthetics and Orthotics International 35, no. 2 (2011): 181–89. http://dx.doi.org/10.1177/0309364611409617.
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Background: Articulated or hinged ankle-foot orthosis (AFO) allow more range of motion. However, quantitative investigation on articulated AFO is still sparse.Objective: The objective of the study was to quantitatively investigate effects of alignment and joint types on mechanical properties of the thermoplastic articulated AFO.Study design: Tamarack dorsiflexion assist flexure joints with three durometers (75, 85 and 95) and free motion joint were tested. The AFO joint was aligned with the center of the motor shaft (surrogate ankle joint), 10 mm superior, inferior, anterior and posterior with respect to the motor shaft center.Methods: The AFO was passively moved from 20° plantar flexion to 15° dorsiflexion at a speed of 10°/s using a motorized device. Mechanical properties including index of hysteresis, passive resistance torque and quasi-static stiffness (at neutral, 5°, 10° and 15° in plantar flexion) were quantified.Results: Significant effects of joint types and joint alignment on the mechanical properties of an articulated thermoplastic AFO were revealed. Specifically, center alignment showed minimum resistance and stiffness while anterior and posterior alignment showed significantly higher resistance and stiffness. The dorsiflexion assist torques at neutral position ranged from 0.69 ± 0.09 to 1.88 ± 0.10 Nm.Conclusions: Anterior and posterior alignment should be avoided as much as possible.Clinical relevanceThe current study suggested that anterior and posterior alignment be avoided as much as possible in clinical practice due to potential skin irritation and increase in stress around the ankle joint.
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Parekh, Selene, Samuel Adams, James Nunley, et al. "Mechanically Superior Molybdenum Rhenium (MoRe®) Alloy provides an advanced option for Foot and Ankle Implants." Foot & Ankle Orthopaedics 3, no. 3 (2018): 2473011418S0037. http://dx.doi.org/10.1177/2473011418s00376.
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Category: Other Introduction/Purpose: One of the most common complications in orthopaedic surgery of the foot and ankle is nonunion or delayed union and bone or implant fractures. Although foot and ankle surgery has improved dramatically over the past decades primarily due to the development of better techniques, little progress has been made in the development of new materials for implants. Titanium, the most commonly used alloy for foot and ankle implants, has limited strength and is notch-sensitive so repetitive stress leads to fatigue failure of implants and limits design options. Better materials with optimized biomechanical properties could result in the development of superior foot and ankle implants and surgical techniques. The mechanical properties of Molybdenum-Rhenium (MoRe®), a promising new alloy for foot and ankle implants were tested. Methods: Standard test methods (ASTM 1717) were performed to evaluate the mechanical properties of Molybdenum Rhenium (MoRe®) alloy compared to Titanium (Ti-6Al-4 V, ASTM F136-13 annealed bar, Ti-ELI). Results: MoRe® is composed purely (99.99%) of molybdenum and rhenium and does not contain Nickel. Molybdenum is found in food and is a cofactor to the enzymes xanthine oxidase and sulfite oxidase, which are essential to bone and connective tissue metabolism. Rhenium is an inert metal with no biological affect. Mechanical testing showed MoRe to be superior to Titanium: Yield Strength: MoRe® 280ksi, Titanium 115ksi, Ultimate Tensile Strength: MoRe® 300ksi, Titanium 125 ksi. Elongation and Reduction in Area: MoRe® 13%, 50%, respectively; Titanium 10%, 25%. Recoil: MoRe® <2%, Titanium 6%. Hardness Range: MoRe® 280-800HV, Titanium 350-400HV. Max Run-Out Load Bent Rod: MoRe® 4.0 mm rod 350 N, Titanium 5.5 mm rod 150 N. Decrease in Max Run-Out Load Bent, Unbent, Re-bent Rod: MoRe® -9%, Titanium -17%. Conclusion: The MoRe® alloy, with its advantageous mechanical properties, offers great promise for the design of a new generation of smaller, stronger and more fatigue resistant foot and ankle implants, resulting in less soft tissue disruption, quicker recovery and better outcomes for patients.
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Zhao, Heng, Yupeng Ren, Yi-Ning Wu, Shu Q. Liu, and Li-Qun Zhang. "Ultrasonic evaluations of Achilles tendon mechanical properties poststroke." Journal of Applied Physiology 106, no. 3 (2009): 843–49. http://dx.doi.org/10.1152/japplphysiol.91212.2008.
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Spasticity, contracture, and muscle weakness are commonly observed poststroke in muscles crossing the ankle. However, it is not clear how biomechanical properties of the Achilles tendon change poststroke, which may affect functions of the impaired muscles directly. Biomechanical properties of the Achilles tendon, including the length and cross-sectional area, in the impaired and unimpaired sides of 10 hemiparetic stroke survivors were evaluated using ultrasonography. Elongation of the Achilles tendon during controlled isometric ramp-and-hold and ramping up then down contractions was determined using a block-matching method. Biomechanical changes in stiffness, Young's modulus, and hysteresis of the Achilles tendon poststroke were investigated by comparing the impaired and unimpaired sides of the 10 patients. The impaired side showed increased tendon length (6%; P = 0.04), decreased stiffness (43%; P < 0.001), decreased Young's modulus (38%; P = 0.005), and increased mechanical hysteresis (1.9 times higher; P < 0.001) compared with the unimpaired side, suggesting Achilles tendon adaptations to muscle spasticity, contracture, and/or disuse poststroke. In vivo quantitative characterizations of the tendon biomechanical properties may help us better understand changes of the calf muscle-tendon unit as a whole and facilitate development of more effective treatments.
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Alt, Wilfried, Heinz Lohrer, and Albert Gollhofer. "Functional Properties of Adhesive Ankle Taping: Neuromuscular and Mechanical Effects Before and After Exercise." Foot & Ankle International 20, no. 4 (1999): 238–45. http://dx.doi.org/10.1177/107110079902000406.
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Best, Raymond, Caroline Böhle, Frieder Mauch, and Peter G. Brüggemann. "Preventive lateral ligament tester (PLLT): a novel method to evaluate mechanical properties of lateral ankle joint ligaments in the intact ankle." Knee Surgery, Sports Traumatology, Arthroscopy 24, no. 4 (2014): 963–70. http://dx.doi.org/10.1007/s00167-014-3190-3.
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Ruiz, Roxa, Lukas Zwicky, and Beat Hintermann. "Syndesmotic Instability After Total Ankle Replacement." Foot & Ankle Orthopaedics 3, no. 3 (2018): 2473011418S0010. http://dx.doi.org/10.1177/2473011418s00103.
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Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement (TAR) evolved over the last decades and has been shown to be an effective concept in the treatment of ankle osteoarthritis (OA). In three-component designs, the second interface between polyethylene insert (PI) and tibial component allows the PI to find its position according the individual physiological properties. This was believed to decrease shear forces within the ankle joint. However, it is not clarified to which extent such an additional degree of freedom may overload the ligamentous structures of the ankle joint over time. This may in particular be the case for the syndesmotic ligaments. Therefore, the purpose of this study was to analyze all ankles after TAR that showed a symptomatic overload of the syndesmotic ligaments and to determine the potential consequences. Methods: Between 2003 and 2017, 31 ankles (females, 17; males 14; mean age 60 [40-79] years) were treated with a tibio-fibular fusion for a symptomatic instability of the syndesmosis. The indication for TAR was posttraumatic OA in 27 (87%), primary OA in 3 (10%), and hemochromatosis in one ankle (3%). The 31 ankles included 23 primary TAR (74%), 6 revision TAR (19%), and two take-down of a fusion and conversion to TAR (7%). Criteria for fusion were the presence of at least two of the followings: (1) tenderness over the syndesmosis, (2) pain while compressing the fibula against the tibia (squeeze test), (3) pain while rotating the foot externally (external rotation test), (4) widening of the syndesmosis on an anteroposterior view. Alignment of TAR (tibial articular surface [TAS] angle) and hindfoot alignment were measured on standard radiographs. Intraoperatively, the syndesmotic instability was confirmed before fusion. The wear of PI was documented. Results: After a mean of 63 (range, 4 – 152) months after TAR, all patients evidenced pain at the level of the syndesmosis of at least 3 months. 25 ankles (81%; 24 after posttraumatic OA) showed a widening of the syndesmotic space and 22 ankles (71%) of the medial clear space with lateral translation of the talus. The PI was seen to overlap the tibial component in 15 ankles (48%). Nine ankles (29%) evidenced cyst formation, and eight ankles (26%) showed a decrease in height of the PI; whereas, in 3 ankles (10%) a fracture of the PI was found. A valgus misalignment of the heel was found in 25 ankles (81%), a valgus TAS in 16 (52%) and a varus TAS in 11 ankles (36%). Conclusion: A syndesmotic instability after a three-component TAR apparently occurred mostly after posttraumatic OA, in particular if the heel was left in valgus. If the talus starts to move lateralward, the PI seems to be at risk for increased wear and finally mechanical failure (Figure 1). Therefore, a valgus misaligned heel should always be corrected during TAR implantation. If there is any sign of syndesmotic instability, a fusion should be considered. Further studies must proof whether in cases with a syndesmotic instability the use of a two-component design will be superior, as it stabilizes the talus in the coronal plane.
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Bregman, Daan J. J., Vincent De Groot, Peter Van Diggele, Hubert Meulman, Han Houdijk, and Jaap Harlaar. "Polypropylene Ankle Foot Orthoses to Overcome Drop-Foot Gait in Central Neurological Patients: A Mechanical and Functional Evaluation." Prosthetics and Orthotics International 34, no. 3 (2010): 293–304. http://dx.doi.org/10.3109/03093646.2010.495969.
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The aim of this study was to assess the functional effects and mechanical contribution of Ankle Foot Orthoses (AFO) prescribed to overcome drop-foot gait. We hypothesized that poor functional effects of the AFO relate to insufficient mechanical contribution of the AFO during the swing phase, or unwanted constraining of the ankle during the stance phase. In seven patients with Stroke or Multiple Sclerosis, we determined changes in energy cost of walking resulting from wearing an AFO, as a measure of the functional effects. In addition, an instrumented gait analysis was performed, and the mechanical AFO properties were measured, to calculate the mechanical contribution of the AFO. The AFO was sufficiently stiff to effectively support the foot in swing, without hampering the ankle during stance. For the whole group, there was a significant improvement in walking speed and energy cost (12%). However, the AFO had no functional benefit in terms of a reduced energy cost of walking for three patients, who coherently demonstrated no pathological plantar flexion during swing without their AFO. We conclude that functional benefit from the AFO was only found when the mechanical AFO characteristics met the need to support the patients‘ mechanical deficiencies.
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Enomoto, Shota, Tomonari Shibutani, Yu Akihara, Miyuki Nakatani, Kazunori Yamada, and Toshiaki Oda. "Acute Effects of Dermal Suction on Passive Muscle and Joint Stiffness." Healthcare 9, no. 11 (2021): 1483. http://dx.doi.org/10.3390/healthcare9111483.
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The aim of the present study was to examine the acute effects of dermal suction on the passive mechanical properties of specific muscles and joints. Dermal suction was applied to the calves of 24 subjects. Passive plantar flexion torque was measured with the right knee fully extended and the right ankle positioned at 20°, 10°, 0°, and −10° angles, where 0° represents the ankle neutral position, and positive values correspond to the plantar flexion angle. The shear wave velocity (SWV) (m/s) of the medial gastrocnemius was measured in the same position using ultrasound shear wave elastography. The relationship between the joint angle and passive torque at each 10° angle was defined as passive joint stiffness (Nm/°). Passive muscle and joint stiffness were measured immediately before and after the dermal suction protocol. When the ankle joint was positioned at 20° (r = 0.53, P = 0.006), 10° (r = 0.43, P = 0.030), and −10° (r = 0.60, P = 0.001), the SWV was significantly higher after dermal suction than that before dermal suction. Regarding joint stiffness, we found no significant difference between the pre- and post-dermal suction values (partial η2 = 0.093, P > 0.05). These findings suggest that dermal suction increases passive muscle stiffness and has a limited impact on passive joint stiffness.
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Deng, Liqin, Xini Zhang, Songlin Xiao, Baofeng Wang, and Weijie Fu. "Gender Difference in Architectural and Mechanical Properties of Medial Gastrocnemius–Achilles Tendon Unit In Vivo." Life 11, no. 6 (2021): 569. http://dx.doi.org/10.3390/life11060569.
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This study aims to explore whether gender differences exist in the architectural and mechanical properties of the medial gastrocnemius–Achilles tendon unit (gMTU) in vivo. Thirty-six healthy male and female adults without training experience and regular exercise habits were recruited. The architectural and mechanical properties of the gMTU were measured via an ultrasonography system and MyotonPRO, respectively. Independent t-tests were utilized to quantify the gender difference in the architectural and mechanical properties of the gMTU. In terms of architectural properties, the medial gastrocnemius (MG)’s pennation angle and thickness were greater in males than in females, whereas no substantial gender difference was observed in the MG’s fascicle length; the males possessed Achilles tendons (ATs) with a longer length and a greater cross-sectional area than females. In terms of mechanical properties, the MG’s vertical stiffness was lower and the MG’s logarithmic decrement was greater in females than in males. Both genders had no remarkable difference in the AT’s vertical stiffness and logarithmic decrement. Gender differences of individuals without training experience and regular exercise habits exist in the architectural and mechanical properties of the gMTU in vivo. The MG’s force-producing capacities, ankle torque, mechanical efficiency and peak power were higher in males than in females. The load-resisting capacities of AT were greater and the MG strain was lesser in males than in females. These findings suggest that males have better physical fitness, speed and performance in power-based sports events than females from the perspective of morphology and biomechanics.
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Adiputra, Dimas, Nurhazimah Nazmi, Irfan Bahiuddin, et al. "A Review on the Control of the Mechanical Properties of Ankle Foot Orthosis for Gait Assistance." Actuators 8, no. 1 (2019): 10. http://dx.doi.org/10.3390/act8010010.
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In the past decade, advanced technologies in robotics have been explored to enhance the rehabilitation of post-stroke patients. Previous works have shown that gait assistance for post-stroke patients can be provided through the use of robotics technology in ancillary equipment, such as Ankle Foot Orthosis (AFO). An AFO is usually used to assist patients with spasticity or foot drop problems. There are several types of AFOs, depending on the flexibility of the joint, such as rigid, flexible rigid, and articulated AFOs. A rigid AFO has a fixed joint, and a flexible rigid AFO has a more flexible joint, while the articulated AFO has a freely rotating ankle joint, where the mechanical properties of the AFO are more controllable compared to the other two types of AFOs. This paper reviews the control of the mechanical properties of existing AFOs for gait assistance in post-stroke patients. Several aspects that affect the control of the mechanical properties of an AFO, such as the controller input, number of gait phases, controller output reference, and controller performance evaluation are discussed and compared. Thus, this paper will be of interest to AFO researchers or developers who would like to design their own AFOs with the most suitable mechanical properties based on their application. The controller input and the number of gait phases are discussed first. Then, the discussion moves forward to the methods of estimating the controller output reference, which is the main focus of this study. Based on the estimation method, the gait control strategies can be classified into subject-oriented estimations and phase-oriented estimations. Finally, suggestions for future studies are addressed, one of which is the application of the adaptive controller output reference to maximize the benefits of the AFO to users.
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Yim, JongEun, Jerrold Petrofsky, and Haneul Lee. "Correlation between Mechanical Properties of the Ankle Muscles and Postural Sway during the Menstrual Cycle." Tohoku Journal of Experimental Medicine 244, no. 3 (2018): 201–7. http://dx.doi.org/10.1620/tjem.244.201.
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Gao, Fan, and Gary G. Bedard. "Effects of Materials, Reinforcement, and Heat Treatment on Thermoplastic Solid Ankle-Foot Orthosis Mechanical Properties." JPO Journal of Prosthetics and Orthotics 25, no. 3 (2013): 143–50. http://dx.doi.org/10.1097/jpo.0b013e31829c163d.
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Banga, Harish Kumar, Parveen Kalra, Rajendra M. Belokar, and Rajesh Kumar. "Customized design and additive manufacturing of kids’ ankle foot orthosis." Rapid Prototyping Journal 26, no. 10 (2020): 1677–85. http://dx.doi.org/10.1108/rpj-07-2019-0194.
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Purpose The purpose of this study is improvement of human gait by customized design of ankle foot orthosis (AFO). An has been the most frequently used orthosis in children with cerebral palsy. AFOs are designed to boost existing features or to avoid depression or traumatize muscle contractures. The advantages of AFO’s utilized for advancement in human walk attributes for the improvement in foot deformities patients or youngsters with spastic loss of motion. In this research on the customized design of AFO's to improve gait, there are limitations during walking of foot drop patients. In children with foot drops, specific AFOs were explicitly altered to improve parity and strength which are beneficial to walking positions. Design/methodology/approach This study proposes the customized design of AFOs using computerized and additive manufacturing for producing advances to alter the design and increase comfort for foot drop patients. Structuring the proposed design fabricated by using additive manufacturing and restricted material, the investigation was finalized at the Design Analysis Software (ANSYS). The system that performs best under investigation can additionally be printed using additive manufacturing. Findings The results show that the customized design of AFOs meets the patient’s requirements and could also be an alternative solution to the existing AFO design. The biomechanical consequences and mechanical properties of additive manufactured AFOs have been comparable to historically synthetic AFOs. While developing the novel AFO designs, the use of 3D printing has many benefits, including stiffness and weight optimization, to improve biomechanical function and comfort. To defeat the issues of foot drop patients, a customized AFO is used to improve the human gait cycle with new material and having better mechanical properties. Originality/value This research work focuses on the biomechanical impacts and mechanical properties of customized 3D-printed AFOs and compares them to traditionally made AFOs. Customized AFO design using 3D printing has numerous potential advantages, including new material with lightweight advancement, to improve biomechanical function and comfort. Normally, new applications mean an incremental collection of learning approximately the behavior of such gadgets and blending the new design, composite speculation and delivered substance production. The test results aim to overcome the new AFO structure issues and display the limited components and stress examination. The outcome of the research is the improved gait cycle of foot drop patients.
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Sinkjaer, T., J. Nielsen, and E. Toft. "Mechanical and electromyographic analysis of reciprocal inhibition at the human ankle joint." Journal of Neurophysiology 74, no. 2 (1995): 849–55. http://dx.doi.org/10.1152/jn.1995.74.2.849.
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1. The purpose of the present study is to investigate how reciprocal inhibition influences the mechanical and electromyographic (EMG) properties of the ankle plantar flexors in humans during a voluntary contraction. 2. At different levels of maintained plantar flexion contractions ranging from 0 to 20 Nm, the size of the soleus EMG stretch reflex and the ankle joint stiffness (ration between the torque increment and the amplitude of the stretch) were measured in response to an imposed dorsiflexion. At matched plantar flexion contraction levels, stretch responses were compared before and after reversible block of the common peroneal nerve (CPN). Stretch responses were also measured during an attempted voluntary fictive dorsiflexion after CPN block. 3. In the preactivated soleus muscles, the phasic EMG response to stretch consisted of two peaks labeled M1 and M2. After CPN block, the M1 short-latency stretch reflex on average increased by 25 +/- 5.7%, mean +/- SD (P < 0.001), and the M2 stretch reflex increased on average by 29 +/- 13.0% (P = 0.002). 4. The total stiffness of the ankle joint during a stretch is the sum of the nonreflex and the reflex mediated stiffness. The total stiffness after CPN block increased on average by 13 +/- 2.7% (P = 0.002) and the estimated reflex stiffness by 33 +/- 6.5% (P < 0.001). 5. When the subjects were asked to make a strong dorsiflexion after CPN block, the soleus stretch reflex was depressed to the extent that the reflex mediated mechanical effect around the ankle joint was abolished.(ABSTRACT TRUNCATED AT 250 WORDS)
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Lin, Kuang-Wei, Chia-Jung Hu, Wen-Wen Yang, et al. "Biomechanical Evaluation and Strength Test of 3D-Printed Foot Orthoses." Applied Bionics and Biomechanics 2019 (December 7, 2019): 1–8. http://dx.doi.org/10.1155/2019/4989534.
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Foot orthoses (FOs) are commonly used as interventions for individuals with flatfoot. Advances in technologies such as three-dimensional (3D) scanning and 3D printing have facilitated the fabrication of custom FOs. However, few studies have been conducted on the mechanical properties and biomechanical effects of 3D-printed FOs. The purposes of this study were to evaluate the mechanical properties of 3D-printed FOs and determine their biomechanical effects in individuals with flexible flatfoot. During mechanical testing, a total of 18 FO samples with three orientations (0°, 45°, and 90°) were fabricated and tested. The maximum compressive load and stiffness were calculated. During a motion capture experiment, 12 individuals with flatfoot were enrolled, and the 3D-printed FOs were used as interventions. Kinematic and kinetic data were collected during walking by using an optical motion capture system. A one-way analysis of variance was performed to compare the mechanical parameters among the three build orientations. A paired t-test was conducted to compare the biomechanical variables under two conditions: walking in standard shoes (Shoe) and walking in shoes embedded with FOs (Shoe+FO). The results indicated that the 45° build orientation produced the strongest FOs. In addition, the maximum ankle evertor and external rotator moments under the Shoe+FO condition were significantly reduced by 35% and 16%, respectively, but the maximum ankle plantar flexor moments increased by 3%, compared with the Shoe condition. No significant difference in ground reaction force was observed between the two conditions. This study demonstrated that 3D-printed FOs could alter the ankle joint moments during gait.
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Yamamoto, S., A. Hagiwara, T. Mizobe, O. Yokoyama, and T. Yasui. "Development of an ankle – foot orthosis with an oil damper." Prosthetics and Orthotics International 29, no. 3 (2005): 209–19. http://dx.doi.org/10.1080/03093640500199455.
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The purpose of the present study was to develop an ankle – foot orthosis (AFO) that satisfies the requirements for an AFO for patients with hemiplegia as determined in a previous study. An oil damper has been introduced as an assistive device. The oil damper provides a resistive moment to plantar flexion of the ankle joint during initial stance on the paretic side. This function improves the insufficient eccentric contraction of the dorsiflexors. The magnitude of the resistive moment generated by this newly developed AFO can be changed easily to adjust its properties in accordance with the requirements of each patient. The mechanical properties of the AFO were measured, and the results showed that the AFO generated a sufficient resistive moment. Hemiplegic gaits with various types of AFOs were assessed, and it was found that the properties of the AFO affected the movements of the ankle, the knee, and the hip joints. The effects of the resistive moment on the alignment of the shank to the floor during initial stance are also discussed. Based on the results of this study, it is concluded that adjustability will be an essential feature for future AFOs.
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Campagnoli, Elena, Sorin Siegler, Maria Ruiz, Alberto Leardini, and Claudio Belvedere. "Effect of Ligament Mapping from Different Magnetic Resonance Image Quality on Joint Stability in a Personalized Dynamic Model of the Human Ankle Complex." Applied Sciences 12, no. 10 (2022): 5087. http://dx.doi.org/10.3390/app12105087.
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Background. Mechanical models of the human ankle complex are used to study the stabilizing role of ligaments. Identification of ligament function may be improved via image-based personalized approach. The aim of this study is to compare the effect of the ligament origin and insertion site definitions obtained with different magnetic resonance imaging (MRI) modalities on the mechanical behaviour of a dynamic model of the ankle complex. Methods. MRI scans, both via 1.5 T and 3.0 T, were performed on a lower-limb specimen, free from anatomical defects, to obtain morphological information on ligament-to-bone attachment sites. This specimen was used previously to develop the dynamic model. A third ligament attachment site mapping scheme was based on anatomical dissection of the scanned specimen. Following morphological comparison of the ligament attachment sites, their effect on the mechanical behaviour of the ankle complex, expressed by three-dimensional load–displacement properties, was assessed through the model. Results. Large differences were observed in the subtalar ligament attachment sites between those obtained through the two MRI scanning modalities. The 3.0 T MRI mapping was more consistent with dissection than the 1.5 T MRI. Load–displacement curves showed similar mechanical behaviours between the three mappings in the frontal plane, but those obtained from the 3.0 T MRI mapping were closer to those obtained from dissection. Conclusions. The state-of-the-art 3.0 T MRI image analysis resulted in more realistic mapping of ligament fibre origin and insertion site definitions; corresponding load–displacement predictions from a subject-specific model of the ankle complex showed a mechanical behaviour more similar to that using direct ligament attachment observations.
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Otegen, D., K. Shomenov, K. Zhangabay, Desmond Adair, and Md Hazrat Ali. "Development of an AFO with Dual-material using an FDM Printer." Journal of Physics: Conference Series 2070, no. 1 (2021): 012200. http://dx.doi.org/10.1088/1742-6596/2070/1/012200.
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Abstract This paper presents a design and development of an Ankle Foot Orthosis (AFO) printed with a multi-extrusion Fused Deposition Modelling (FDM) printer. AFO is crucial in the healing of patients with ankle joint displacement. It helps to heal the foot easily. The model is designed to print with dual materials such as flex and polylactic acid (PLA). The critical problem in building a prototype is to obtain excellent bonding properties between the layers of different materials. The Flex material is softer than the PLA and both have different melting temperatures. Thus, successfully printing with an excellent adhesive is the key concern in multimaterial applications. The paper also presents the simulation results of an AFO to justify the mechanical properties and required materials for sustainable development.
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Abar, Bijan, Cambre N. Kelly, Nicholas B. Allen, et al. "Influence of Topography on 3D printed Titanium Foot and Ankle Implants." Foot & Ankle Orthopaedics 5, no. 4 (2020): 2473011420S0001. http://dx.doi.org/10.1177/2473011420s00016.
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Category: Basic Sciences/Biologics; Ankle; Trauma Introduction/Purpose Foot and ankle etiologies such as traumatic fractures, Charcot Arthropathy, nonunion after high risk arthrodesis and infectious debridement can result in critical sized bone defect (CSD). CSD is defined as bone loss greater than 1-2 cm in length or greater than 50% loss in circumference of bone. CSD remain a significant challenge in Orthopaedics. Custom 3D printed porous Titanium implants are currently being implemented when allograft is not an option. However, in a subset of cases, Titanium implants need to be removed due to infection or poor osseous integration where surrounding bone does not grow onto or through the scaffold. There is no one clear reason for poor osseous integration. This study explores effects of 3D printed topography on mechanical and biological properties. Methods: Titanium dog bones and discs were printed via laser powder bed fusion. Roughness groups were polished, blasted, as built, sprouts and rough sprouts. Roughness was measured with line measurement using a confocal microscope. To assess mechanical properties, tensile testing of samples from each roughness group produced stress strain curves. MC3T3 preosteoblast were seeded on discs. Samples were analyzed at 0, 2, and 4 weeks. A cell viability assay and confocal florescent microscopy assessed cell growth. Alkaline Phosphatase (ALP) assay and Quantitative Polymerase Chain Reaction (qPCR) examined cell differentiation. Extracellular matrix (ECM) was stained for collagen and calcium. Scanning Electron Microcopy (SEM) was done on sputter coated discs. Results: Rz, maximum peak to valley distance of the sample profile, for the polished, blasted, as built, sprouts and rough sprouts were 2.6, 22.6, 33.0, 41.4 and 65.1 µm respectively. The addition of printed roughness in the sprouts and rough sprouts group significantly diminished ductility resulting in early strain to failure during tensile testing. Cells adhered and proliferated on discs regardless of roughness group. There was no statically difference in ALP activity, but qPCR showed that rough groups (sprouts and rough sprouts) had diminished Osteocalcin gene expression at week 2 and 4. The ECM observed with SEM in the rough groups was more resistant to repeated washes and was more extensive compared to the less rough groups. Conclusion: The addition of 3D printed artificial roughness leads to inferior mechanical properties and confers no clear benefit regarding cellular proliferation. Printed topography increases the initiation of fractures resulting in diminished tensile strength and ductility. Concurrently, the resolution of LBF is not fine enough at this time to create surface features that enhance cell behavior. Therefore, data in this study suggest that artificially printing roughness is not an effective strategy to enhance osseous integration into Titanium implants for critical sized defects.
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Valle, Rodrigo, Gonzalo Pincheira, Víctor Tuninetti, Cesar Garrido, Cecilia Treviño, and Jorge Morales. "Evaluation of the Orthotropic Behavior in AN Auxetic Structure Based on a Novel Design Parameter of a Square Cell with Re-Entrant Struts." Polymers 14, no. 20 (2022): 4325. http://dx.doi.org/10.3390/polym14204325.
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In this research, a three-dimensional auxetic configuration based on a known re-entrant cell is proposed. The 3D auxetic cell is configured from a new design parameter that produces an internal rotation angle to its re-entrant elements to study elastic properties in its three orthogonal directions. Through a topological analysis using Timoshenko beam theory, the bending of its re-entrant struts is modeled as a function of the new design parameter to manipulate Poisson’s ratio and Young’s modulus. Experimental samples were fabricated using a fused filament fabrication system using ABS and subsequently tested under quasi-static compression and bending tests. Additionally, an orthotropy factor is applied that allows for measuring the deviation between the mechanical properties of each structure. The experimental results validate the theoretical design and show that this new unit cell can transmit an orthotropic mechanical behavior to the macrostructure. In addition, the proposed structure can provide a different bending stiffness behavior in up to three working directions, which allows the application under different conditions of external forces, such as a prosthetic ankle.
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Caravaggi, Paolo, Alessandro Zomparelli, Giulia Rogati, et al. "Development of a Novel Passive-Dynamic Custom AFO for Drop-Foot Patients: Design Principles, Manufacturing Technique, Mechanical Properties Characterization and Functional Evaluation." Applied Sciences 12, no. 9 (2022): 4721. http://dx.doi.org/10.3390/app12094721.
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Ankle foot orthoses (AFOs) are medical devices prescribed to support the foot and ankle of drop-foot patients. Passive-dynamic AFOs (PD-AFOs) are an effective solution for less severe cases. While off-the-shelf PD-AFOs are rather inexpensive, they provide poor anatomical fit and do not account for the required patient-specific biomechanical support. Three-dimensional (3D) scanning and manufacturing technologies allow manufacturing PD-AFOs customized for the patient’s anatomy and functional needs. This paper aimed to report the overall procedure for designing and manufacturing a novel, fiberglass-reinforced polyamide, custom PD-AFO. The feasibility of the proposed procedure was tested in a case study. The methodology can be divided into the following steps: (i) foot and leg scanning, (ii) 3D design, and (iii) additive manufacturing via selective laser sintering. A custom PD-AFO was designed and manufactured for a 67-year-old male drop-foot patient following paraparesis in severe discarthrosis after spine stabilization surgery. AFO mechanical properties were measured via an ad hoc setup based on a servohydraulic testing machine. The functional outcome was assessed via gait analysis in three conditions: shod (no AFO), wearing an off-the-shelf PD-AFO, and wearing the patient-specific PD-AFO. As expected, wearing the PD-AFO resulted in increased ankle dorsiflexion in the swing phase with respect to the shod condition. Sagittal rotations of the hip, knee, and ankle joints were similar across PD-AFO conditions, but the custom PD-AFO resulted in faster walking speed with respect to the off-the-shelf (walking speed: 0.91 m/s versus 0.85 m/s). Additionally, the patient scored the custom PD-AFO as more comfortable (VAS score: 9.7 vs. 7.3). While the present analysis should be extended to a larger cohort of drop-foot patients, the novel PD-AFO seems to offer a valid, custom solution for drop-foot patients not satisfied with standard orthotics.
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Liu, Yuanjie, Qing Zhou, Shun Gan, and Bingbing Nie. "Influence of population variability in ligament material properties on the mechanical behavior of ankle: a computational investigation." Computer Methods in Biomechanics and Biomedical Engineering 23, no. 2 (2019): 43–53. http://dx.doi.org/10.1080/10255842.2019.1699541.
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Shin, YeJi, and TaeLim Yoon. "The Short Term Effects of Ankle Strengthening Emphasis with Jumping on Strength, Mechanical Properties, and Balance with and without Wearing High Heel in Ankle Instability." Journal of Korean Physical Therapy 31, no. 4 (2019): 176–83. http://dx.doi.org/10.18857/jkpt.2019.31.4.176.
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Darter, Benjamin J., and Jason M. Wilken. "Energetic consequences of using a prosthesis with adaptive ankle motion during slope walking in persons with a transtibial amputation." Prosthetics and Orthotics International 38, no. 1 (2013): 5–11. http://dx.doi.org/10.1177/0309364613481489.
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Background:Technological advances in prosthetic design include the use of microprocessors that adapt device performance based on user motion. The Proprio ankle unit prepositions the foot to adjust for walking on slopes and increases foot clearance during swing to minimize gait deviations.Study design:Comparative analysis.Objectives:To investigate the effect of a prosthesis with adaptive ankle motion on physiological gait performance during slope walking.Methods:Six persons with a unilateral transtibial amputation completed treadmill walking tests at three slopes (−5°, 0°, and 5°). The participants were tested wearing a customary device, active Proprio (Pon), and an identical inactivated Proprio (Poff).Results:Metabolic energy expenditure, energy cost for walking, and rating of walking difficulty were not statistically different between the Pon and Poff for all tested slopes. However, for slope descent, energy expenditure and energy cost for walking improved significantly by an average of 10%–14% for both the Pon and Poff compared to the customary limb. Rating of walking difficulty also showed an improvement with slope descent for both the Pon and Poff compared to the customary device. An improvement with slope ascent was found for Pon compared to the customary limb only.Conclusions:Adaptive ankle motion provided no meaningful physiological benefit during slope walking. The Proprio was, however, less demanding than the customary device for slope descent. Differences in the mechanical properties of the prosthetic feet likely contributed to the changes.Clinical relevanceWhile the adaptive ankle motion did not affect metabolic energy expenditure or energy cost for walking, the results suggest close attention should be paid to the mechanical properties of the foot component. Assessment of gait on nonlevel surfaces is recommended to better understand the implications of different prosthetic design features.
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Pollock, C. M., and R. E. Shadwick. "Relationship between body mass and biomechanical properties of limb tendons in adult mammals." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 266, no. 3 (1994): R1016—R1021. http://dx.doi.org/10.1152/ajpregu.1994.266.3.r1016.
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We investigated the allometric relationship between the mechanical properties of various limb tendons and body mass. The elastic modulus (i.e., stiffness) and hysteresis (i.e., energy dissipation) of digital flexor, ankle extensor, and digital extensor tendons from 18 species of adult quadrupedal mammals ranging in body mass from 0.5 to 545 kg were determined by cyclic tensile testing in vitro. The results show that these elastic properties do not vary significantly among tendons from animals of different body mass, nor do they differ between the digital flexor and ankle extensor tendons (those situated to act as springs during locomotion) and the digital extensor tendons (those not likely to function as springs during locomotion). Consequently, the inherent capability of different limb tendons to store elastic energy, based on their material properties, is the same for large and small animals. The relationship between tendon elastic modulus (E; in GPa) and body mass (Mb; in kg) is described by the allometric equation E = 1.22Mb0.00. The hysteresis (H), as a percentage of total strain energy, is related to body mass as H = 8.89Mb-0.03.
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Muralidharan, Laxmi, Philip Cardiff, Karen Fitzgerald, Robert Flavin, and Alojz Ivanković. "A patient-specific numerical model of the ankle joint for the analysis of contact pressure distribution." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 234, no. 9 (2020): 909–20. http://dx.doi.org/10.1177/0954411920932687.
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A patient-specific numerical model of the ankle joint has been developed using open-source software with realistic material properties that mimics the physiological movement of the foot during the stance phase of the gait cycle. The patient-specific ankle geometry has been segmented as a castellated surface using 3DSlicer from the computed tomography image scans of a subject with no congenital or acquired pathology; subsequently, the bones are smoothed, and cartilage is included as a uniform thickness extruded layer. A high-resolution Cartesian mesh has been generated using cfMesh. The material properties are assigned in the model based on the CT image Hounsfield intensities and compared to a sandwich-based material model. Gait data of the same subject was obtained and used to relatively position the tibia, talus, and calcaneus bones in the model. The stance phase of the gait cycle is simulated using a cell-centred finite-volume method implemented in open-source software OpenFOAM. The predicted peak contact pressures occur in the range of 4.85–5.53 MPa with average pressures in the range of 1.56–1.95 MPa, and the contact area ranges between 429 and 707.8 mm2 for the entire stance phase with the mid-stance phase predicting the maximum contact area. These predictions are in agreement with results from the literature. The effect of arthritis on the contact characteristics of the ankle joint has also been examined. A concentrated increase in pressure was predicted that could be manifested as pain, thereby leading to reduced motion in the ankle. The model, with continued development, has the capability to understand the effect of joint degradation and furthermore, could help provide a tool to predict the efficiency of therapeutic surgical procedures as well as guide the development of next generation ankle prostheses. The work would be made available in the University College Dublin depository ( https://github.com/laxmimurali/anklejoint ) as well as research gate once the article has been published.
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Cordier, Guillaume, Gustavo Araujo Nunes, and Miki Dalmau-Pastor. "The mechanical effect of the common fibers of the anterior talofibular and calcaneofibular ligaments." Orthopaedic Journal of Sports Medicine 9, no. 2_suppl (2021): 2325967121S0000. http://dx.doi.org/10.1177/2325967121s00008.
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Objectives: The subject of the lateral ankle ligament complex is a familiar one. Common fibers between the inferior bundle of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) have been described. The purpose of this study is to investigate the possibility of transmitting a force to the CFL through the inf. ATFL. Methods: An anatomical study was carried out on 12 ankles. Each specimen was dissected according to a protocol to expose the lateral ligaments. A proximal section was made in the superior and inferior bands of the anterior talofibular ligament. A device capable of measuring shifting from one point in relation to another fixed point was used. The fixed point was implanted on the calcaneus and the other part of the sensor on the CFL. Traction of 1-kilogram was applied to the inferior band of the ATFL while the device measured the shifting of the CFL in millimeters. Two measurements were taken on each specimen by two observers. Sample data and distance measurements were recorded and analyzed. Results: It was possible to analyze 12 specimens. The specimens were from 7 women and 5 men and included 6 right and 6 left ankles. The anterior talofibular ligament was identified as a two-band ligament in all cases. One ankle had a lesion on the superior band of the ATFL. Common fibers that connect the inferior ATFL and the CFL were observed in all samples of this study. The measuring device showed shifting of the CFL in each case. The first series of measurements indicated average shifting of 0.74 mm (0.46; 1.35; +/- 0.34) and a median of 0.59 mm. The second series indicated a mean of 0.60 mm (0.23 - 1.13; +/- 0.32) and a median of 0.46 mm. Conclusion: There is an anatomical connection between the inferior ATFL and the CFL that is capable of transmitting a mechanical force to the CFL when the inferior ATFL is placed in traction. Improvement in the knowledge of the mechanical properties of the lateral ligament plane helps to clarify the possibilities for surgical repairs.
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Oba, Kensuke, Mina Samukawa, Yosuke Abe, et al. "Effects of Intermittent and Continuous Static Stretching on Range of Motion and Musculotendinous Viscoelastic Properties Based on a Duration-Matched Protocol." International Journal of Environmental Research and Public Health 18, no. 20 (2021): 10632. http://dx.doi.org/10.3390/ijerph182010632.
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The different effects of intermittent and continuous stretching on the mechanical properties of the musculotendinous complex have been unclear. This study aimed to compare the effects of intermittent and continuous stretching for the same duration on the range of motion (ROM), passive resistive torque (PRT), and musculotendinous stiffness (MTS) of ankle plantar flexors. Eighteen healthy young men participated in the study. Intermittent (four sets × 30 s) and continuous stretching (one set × 120 s) were performed in random orders on two separate days. Both stretching protocols were conducted using a dynamometer with a constant torque applied. ROM and PRT were determined using a dynamometer, and MTS was calculated using the torque–angle relationship measured before and after stretching. Two-way repeated measures analysis of variance was performed for all parameters. Both intermittent and continuous stretching significantly increased ROM and decreased PRT and MTS (p < 0.05). Intermittent stretching led to greater changes in ROM and PRT than continuous stretching. However, the reduction in MTS did not differ between the two conditions. These results suggest that intermittent stretching is more effective in increasing ROM and changing the mechanical properties of the musculotendinous complex.
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Kadhum, Murtaza, Mu-Huan Lee, Jan Czernuszka, and Chris Lavy. "An Analysis of the Mechanical Properties of the Ponseti Method in Clubfoot Treatment." Applied Bionics and Biomechanics 2019 (March 25, 2019): 1–11. http://dx.doi.org/10.1155/2019/4308462.
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Congenital clubfoot is a complex pediatric foot deformity, occurring in approximately 1 in 1000 live births and resulting in significant disability, deformity, and pain if left untreated. The Ponseti method of manipulation is widely recognized as the gold standard treatment for congenital clubfoot; however, its mechanical aspects have not yet been fully explored. During the multiple manipulation-casting cycles, the tendons and ligaments on the medial and posterior aspect of the foot and ankle, which are identified as the rate-limiting tissues, usually undergo weekly sequential stretches, with a plaster of Paris cast applied after the stretch to maintain the length gained. This triggers extracellular matrix remodeling and tissue growth, but due to the viscoelastic properties of tendons and ligaments, the initial strain size, rate, and loading history will affect the relaxation behavior and mechanical strength of the tissue. To increase the efficiency of the Ponseti treatment, we discuss the theoretical possibilities of decreasing the size of the strain step and interval of casting and/or increasing the overall number of casts. This modification may provide more tensile stimuli, allow more time for remodeling, and preserve the mechanical integrity of the soft tissues.
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Leahy, Thomas P., Courtney A. Nuss, Mary Kate Evans, Ashley K. Fung, Snehal S. Shetye, and Louis J. Soslowsky. "Achilles Tendon Ruptures in Middle-Aged Rats Heal Poorly Compared With Those in Young and Old Rats." American Journal of Sports Medicine 50, no. 1 (2021): 170–81. http://dx.doi.org/10.1177/03635465211055476.
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Background: Achilles tendon ruptures are painful and debilitating injuries and are most common in middle-aged patients. There is a lack of understanding of the underlying causes for increased rupture rates in middle-aged patients and how healing outcomes after a rupture might be affected by patient age. Therefore, the objective of this study was to define age-specific Achilles tendon healing by assessing ankle functional outcomes and Achilles tendon mechanical and histological properties after a rupture using a rat model. Hypothesis: Rats representing the middle-aged patient population would demonstrate reduced healing capability after an Achilles tendon rupture, as demonstrated by a slower return to baseline ankle functional properties and inferior biomechanical and histological tendon properties. Study Design: Controlled laboratory study. Methods: Fischer 344 rats were categorized by age to represent young, middle-aged, and old patients, and Achilles tendon ruptures were induced in the right hindlimb. Animals were allowed to heal and were euthanized at 3 or 6 weeks after the injury. In vivo functional assays and ultrasound imaging were performed throughout the healing period, and ex vivo tendon mechanical and histological properties were assessed after euthanasia. Results: Rats representing middle-aged patients displayed reduced healing potential compared with the other age groups, as they demonstrated decreased recovery of in vivo functional and ultrasound assessment parameters and inferior mechanical and histological properties after an Achilles tendon rupture. Conclusion: These findings may help explain the increased rupture rate observed clinically in middle-aged patients by suggesting that there may be altered tendon responses to daily trauma. Clinical Relevance: The results provide novel data on age-specific healing outcomes after an Achilles tendon rupture, which underscores the importance of considering a patient’s age during treatment and expectations for outcomes.
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Bartholomew, Ania, Tyler Slone, Michael Ciesa, Nicholas A. Cheney, and Brian C. Clark. "Analysis of Complications Following Distal Ankle Nerve Blocks for Foot and Ankle Procedures." Foot & Ankle Orthopaedics 7, no. 1 (2022): 2473011421S0010. http://dx.doi.org/10.1177/2473011421s00104.
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Category: Ankle; Arthroscopy; Bunion; Hindfoot; Midfoot/Forefoot; Other Introduction/Purpose: Popliteal nerve blocks are a common procedure employed by anesthesiologists to augment intraoperative anesthesia and provide postoperative pain control. Unfortunately, these can be associated with unintended complications including pain, numbness, and foot drop, sometimes without clear resolution. Studies from Kahn (2017), Anderson (2015), Park (2018), Lauf (2020) suggest complications higher than previously reported with Lauf (2020) finding short-term complication rates of 10.1% and 4.1% long-term as confirmed by EMG. Our study looked to address the complication rates from an alternative anesthetic procedure, a distal ankle nerve block involving anesthesia to the five nerve(s) more intimately involved in the surgical procedure. This alternative technique may provide equivalent anesthetic properties and pain relief as popliteal blocks, with fewer complications for many patients across various demographics. Methods: We retrospectively reviewed patient charts and messaging from 2019 to 2021 that received a distal ankle field block for various surgical procedures including ankle arthroscopy, ankle fractures, and lateral ankle stabilizations. The five nerves anesthetized in the distal ankle nerve block included the tibial, superficial and deep peroneal, sural, and saphenous. Thus far, 61 surgeries have been reviewed and analyzed for neuropathic complications and confirmed via EMG. Results: Of the 61 patients analyzed, 3 patients were found to have a superficial peroneal neuropathy that included dorsal numbness as a result of the distal ankle block, resulting in a 4.92% complication rate. 1 patient required a rescue block to be performed postoperatively for pain. The remaining 57 patients recovered appropriately and without complications. No motor complications have been found from patients receiving distal ankle nerve blocks, as performed by the senior author. Conclusion: With the absence of motor complications and markedly reduced incidence of sensory complications, distal ankle nerve blocks may be a beneficial alternative to popliteal nerve blocks for various foot and ankle orthopedic surgeries. As motor complications can result in life-altering disability, an anesthetic procedure with reduced negative motor outcomes can improve surgery and recovery prognosis. Future directions for this study include adding more patients to increase the sample size, as well as continuing to follow current patients, monitoring symptoms or complications.
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Sonda, Francesca C., Mariana O. Borges, Emmanuel S. Rocha, Anelize Cini, Marco A. Vaz, and Claudia S. Lima. "The effects of a 10-minute triceps surae stretching session persist after 60 min: a randomized clinical trial." Brazilian Journal of Motor Behavior 16, no. 3 (2022): 276–90. http://dx.doi.org/10.20338/bjmb.v16i3.292.
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BACKGROUND: Stretching exercises increase the joint range of motion (ROM) and depend on the skeletal tissues' exposition-time to stretch. However, it is unclear how a long stretching time affects the muscle-tendon unit's passive mechanical properties. AIM: This study aimed to analyze changes in the triceps surae muscle-tendon unit’s passive mechanical properties before and after a 10-minute passive stretching protocol. METHOD: Thirty healthy participants (26.57 ± 3.82 years old) were allocated into a control group (n=15), who did not perform any intervention, and to an experimental group (n=15), who performed one bout of a 10-minute ankle plantar flexor passive static stretching. Ankle ROM, plantar flexor passive torque, and myotendinous junction displacement were evaluated pre-intervention, immediately after, and 15, 30, 45, and 60 minutes after the end of the intervention. The stiffnesses of the muscle-tendon unit, muscle, and tendon were calculated for all moments. A generalized estimating equation test was performed to compare groups and moments. RESULTS: The experimental group increased the ROM (p<0.001) from pre- to post-intervention and remained augmented up to 60 minutes. The myotendinous junction displacement decreased at post-30 and post-45 moments compared to pre-intervention. Muscular stiffness increased immediately after stretching and post-45 and post-60 minutes. Passive torque and musculotendinous unit stiffness decreased over time, with trivial, small, and moderate effect sizes, respectively. CONCLUSION: Passive static stretching (10 min) generates an acute ROM increase associated with muscle-tendon unit passive mechanical properties reduction, which lasts up to one-hour post-intervention.
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Tamošiūnas, Justas, and Vytautas Bučinskas. "Research of the dynamical properties of mechatronic prosthesis." Robotic Systems and Applications 2, no. 2 (2022): 29–42. http://dx.doi.org/10.21595/rsa.2022.22678.
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The mechatronic ankle prosthesis plays a crucial role in the recreation of natural gait biomechanics by being able to actively control time-torque parameters in different sub-phases of the walking cycle. This paper presents a methodology for improving the design process of the individual characteristics of the object of interest. A series of tests were taken to derive a correlation between an actual structure and a developed mathematical model to determine the parameters of the object under investigation. The model provides a possibility to determine time-changing force-related properties to capture a full picture of the structure for which a particular design is being chosen. The method also acts as a tool to expand traditional design criteria to get the overall view of the structural dynamics of the mechanical system.
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Hasson, Christopher J., Richard E. A. van Emmerik, and Graham E. Caldwell. "Balance Decrements Are Associated With Age-Related Muscle Property Changes." Journal of Applied Biomechanics 30, no. 4 (2014): 555–62. http://dx.doi.org/10.1123/jab.2013-0294.
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In this study, a comprehensive evaluation of static and dynamic balance abilities was performed in young and older adults and regression analysis was used to test whether age-related variations in individual ankle muscle mechanical properties could explain differences in balance performance. The mechanical properties included estimates of the maximal isometric force capability, force-length, force-velocity, and series elastic properties of the dorsiflexors and individual plantarflexor muscles (gastrocnemius and soleus). As expected, the older adults performed more poorly on most balance tasks. Muscular maximal isometric force, optimal fiber length, tendon slack length, and velocity-dependent force capabilities accounted for up to 60% of the age-related variation in performance on the static and dynamic balance tests. In general, the plantarflexors had a stronger predictive role than the dorsiflexors. Plantarflexor stiffness was strongly related to general balance performance, particularly in quiet stance; but this effect did not depend on age. Together, these results suggest that age-related differences in balance performance are explained in part by alterations in muscular mechanical properties.
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Rogati, G., P. Caravaggi, A. Leardini, et al. "A novel apparatus to assess the mechanical properties of Ankle-Foot Orthoses: Stiffness analysis of the Codivilla spring." Journal of Biomechanics 142 (September 2022): 111239. http://dx.doi.org/10.1016/j.jbiomech.2022.111239.
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Stefańczak, D., J. Gajewski, and M. Rogala. "Application of the finite element method to the design of an ankle orthosis." Journal of Physics: Conference Series 2130, no. 1 (2021): 012013. http://dx.doi.org/10.1088/1742-6596/2130/1/012013.
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Abstract AFO (Ankle-Foot Orthosis), which covers the ankle and foot, protects and supports the ankle joint as well as the structures around it. It contributes to the maintenance of the correct gait cycle. Owing to orthoses, the functional capacity of the body part is significantly improved, and so is the quality of life for the user. Personalized orthoses, which are adapted to the anatomy of the user, are more and more often produced by the additive methods. The use of 3D printing for the manufacturing medical devices is becoming increasingly common due to the low cost of the whole process, short production time and the possibility of the product personalization. One of the stages in manufacturing AFOs with the additive method is to create a three-dimensional model of the orthosis in CAD software. Finite element analysis was performed to assess the mechanical properties of the orthosis. The influence of geometry and the materials used were investigated with FEM analysis software. As a result of structural analysis during the design stage, the assessment of the medical device in terms of its durability and mechanical resistance without putting the user at risk is possible. On the basis of the obtained results, the structure strength was compared.